Autodiff CI job

The optional-x86_64-gnu-autodiff job provides continuous test coverage for the experimental autodiff feature and its integration with LLVM Enzyme. It is an optional auto job, so a failure does not prevent a pull request from being merged.

For more context about the feature, see the autodiff tracking issue and the autodiff internals chapter.

What is tested

The job checks:

• forward- and reverse-mode macro expansion and diagnostics;
• LLVM IR generation for autodiff;
• enforcement of the autodiff feature gate.

Running the job

To run the job in a try build, comment on a pull request:

@bors try jobs=optional-x86_64-gnu-autodiff

To run the job locally, run this command from a Rust checkout:

$ cargo run --manifest-path src/ci/citool/Cargo.toml run-local optional-x86_64-gnu-autodiff

See Testing with Docker for more information about running CI jobs locally.

Point of contact

If you have questions or need help with a failure in this job, open a new topic in the autodiff Zulip channel. For suspected Enzyme backend failures, see the autodiff debugging guide.